No. 2303. RED SPIDERS OF AMERICA— McGREOOR. 668 



and backward from the pore, then turns suddenly upward and back- 

 ward to form an angle of about 130°, and then the superior arm 

 bends abruptly forw^ard and upward, paralleling the inferior arm. 

 The superior arm is much shorter and of somewhat smaller caliber 

 than the inferior arm. The penis (pi. 79, fig. 3) is of unusual type. 

 The short inner lobe is rod-like for most of its length and then ex- 

 pands suddenly to form the prominent basilar lobe; the outer shaft 

 arises as a rod-like structure not materially stouter than the inner 

 lobe, and for one-third its length is dh'ected about continuous with 

 the inner lobe, but bends slightly dowiiv/ard, then extending back- 

 ward as a straight, slender spur, terminating in a very sharp point. 



Type.— Cat. No. 20165, U.S.N.M. 



From the south slope of Mount Hood, Oregon, above Government 

 Camp, at an altitude of 6,000 feet, from underside of leaves of large- 

 berried hucklel)erry {Vaccinium, species). Considerable discolora- 

 tion and dropping of leaves accompanies the mite's activities. The 

 species is rather close to T. oregonensis , but is readily distinguished 

 from the latter through the marked difference in the form of the 

 penis and collar trachea. 



SEPTANYCHUS, new genus. 



This genus at present represented by two species from the United 

 States. 



Tarsus with empodial claw separated at base from distal portion 

 of tarsus; claw complex, appendiculate at or near base with four to 

 six spurs; the dorsal spur decidedly shorter than the ventral group 

 of spm'S. 



KEY TO SPECIES OF GENUS SEPT.VNYCHU.S. 



a^ Terminal "finger" of palpal "thumb"' in width at base exceeding its length; 

 dorsal "finger" fully as long as terminal "finger;" mandibular plate converging 

 to a well-rounded anterior margin S. tuvndits Banks. 



a^. Terminal "finger" of palpal "thumb" about half again as long as wide; dorsal 

 "finger" onlj' about two-thirds the length of the terminal "finger;" mandibular 

 plate with subparallel sides, and subtrunrate frontal margin. 



6\ qtdnquenychua McGregor. 



SEPTANYCHUS TUMIDUS (Banks). 



Tetranychus twnidus Banks, 1900. Tech. Bull. No. 8, Div. of Ent., U. S. Dept. of 

 Agric, p. 73. 



The following description of S. iumidus is taken chiefly from 

 Banks's (9) original paper, with such alterations as have been found 

 necessar}^ through a close study of the type material: 



Dark red and somewhat pruinoee, marked across the thorax with a dusky band, 

 terminating each side in a rather large dusky spot, a similar spot on each side near end 



